July 10 (Reuters) - GSI Group Inc, which supplies precision technology and semiconductor systems, said it agreed to buy photonics-based solutions maker Excel Technology Inc in an all-cash deal for $360 million to expand its market presence. The offer price of $32 per share, before fees and transaction costs, represents a 30.2 percent premium to the average Excel closing price over the last 30 trading days, GSI said in a statement.
